The present invention generally relates to engine control systems, and more specifically, but not exclusively, relates to a technique for managing torque of a drivetrain based upon the operating state of an associated transmission.
The front end of a drivetrain for a vehicle primarily comprises an internal combustion engine (hereinafter xe2x80x9cenginexe2x80x9d), and a transmission having a torque converter operatively coupled to an output shaft of the engine. For such vehicles also having an electronically controlled fueling system, a controller utilizes a first torque curve for direct drive gear ratios when computing a fueling meter signal for the fueling system and utilizes a second lower torque curve for other gear ratios when computing the fueling meter signal. Consequently, the gears of the transmission are protected from structural damage or destruction due to an inordinate amount of torque being applied to the torque converter from the engine output shaft. To protect additional drivetrain components downstream from the transmission, both torque curves can be mapped in view of the lowest maximum torque capacity of a downstream component. Alternatively, in addition to computing a fueling meter signal from the appropriate torque curve, the controller can compute a separate fueling meter signal for each downstream component as a function of the maximum torque capacity of each downstream component, and then provide the lowest computed fueling meter signal to the fueling system. However, this technique for computing a fueling meter signal does not address a need to protect the transmission whenever the torque converter is in a stall or high slip condition. The present invention addresses this need, and provides other important benefits and advantages.
The present invention relates to a technique for managing torque of an internal combustion engine based upon the operating state of an associated transmission. Various aspects of the present invention are novel, nonobvious, and provide various advantages. While the actual nature of the invention covered herein can only be determined with reference to the claims appended hereto, certain features which are characteristic of the preferred embodiment disclosed herein are described briefly as follows.
One embodiment of the present invention is a unique engine control system. Other embodiments include, but are not limited to, unique methods and devices to regulate torque in a drivetrain.
A further embodiment includes a unique technique to manage torque capacity relative to a torque converter of an automatic transmission.
A still further embodiment includes a unique technique to limit torque developed in a drivetrain including an engine mechanically coupled to a transmission. The torque limit is at least partially determined in accordance with the gear ratio of the transmission. In one form of this embodiment, torque limit is selected as the lowest of a number of different possible limits.
One object of the present invention is to provide an improved torque management technique.
Another object of the present invention is to provide a torque management technique for computing a fueling meter signal corresponding to the maximum torque capacity.